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Tumor Discovery

ORIGINAL RESEARCH ARTICLE
Exploring somatic mutations in

POLE and POLD1: Their role in colorectal
cancer pathogenesis and potential

therapeutic strategies

Hersh Abdul Ham-Karim * , Narmeen Salih Ahmad 2 , and
1
Mohammad Ilyas 3,4
1 Pharmacy department, College of Medicine, Komar University of Science and Technology,
Sulaymaniyah, Iraq
2 Department Microbiology, Faculty Health and Biomedicine, Kurdistan Institution for Strategic
Studies and Scientific Research, Sulaimani, Iraq
3 Nottingham Molecular Pathology Node, Faculty Medicine and Health Sciences, University of
Nottingham, Nottingham, United Kingdom

Abstract

Colorectal cancer (CRC) is one of the major causes of morbidity and mortality worldwide,
resulting from the accumulation of genetic and epigenetic alterations in several
oncogenes and tumor suppressor genes. Recent studies have identified germline and
somatic mutations in the exonuclease domain regions of both epsilon polymerase
(POLE) and delta polymerase (POLD1) genes in CRCs. We sought to examine the mutation
*Corresponding author:
Hersh Abdul. Ham-Karim of these genes in a series of sporadic CRCs. To do this, we extracted DNA from 100
(hersh.abdul@komar.edu.iq) primary CRC samples and 40 corresponding normal tissue samples, which had been
previously characterized for clinicopathological and molecular features. We employed
Citation: Ham-Karim HA,
Ahmad NS, Ilyas M. Exploring a combination of quick-multiplex consensus (QMC)-polymerase chain reaction (PCR)
somatic mutations in POLE and and co-amplification at lower denaturation temperature (COLD)-PCR, followed by high-
POLD1: Their role in colorectal resolution melting (HRM) analysis and Sanger sequencing, to investigate the exonuclease
cancer pathogenesis and potential
therapeutic strategies. Tumor domain regions of POLE and POLD1 genes for somatic mutations that may potentially alter
Discov. 2024;3(3):3659. the proofreading activities of these genes. In silico predictions of the functional significance
doi: 10.36922/td.3659 of the identified genetic alterations were performed using the protein variation effect
Received: May 14, 2024 analyzer, sorting intolerant from tolerant, and PON-P2 algorithms. We identified a total
Accepted: July 17, 2024 of eight new and non-recurrent somatic variants in the endonuclease domains of POLE
and two in POLD1. Nine out of ten variants caused amino acid substitutions, whereas one
Published Online: September 6, 2024 resulted in a stop codon. Although no significant associations or correlations were found
Copyright: © 2024 Author(s). between the POLE/POLD1 mutations and the clinicopathological or molecular features of
This is an Open-Access article the CRC cases, most of the POLE/POLD1-mutated cases were microsatellite stable (90%)
distributed under the terms of the
Creative Commons Attribution and aneuploid (80%). Furthermore, in silico analyses showed that nine of the ten variants
License, permitting distribution, would likely cause some adverse effect on protein function. Ten somatic variants with
and reproduction in any medium, predicted proofreading activity-altering effects have been identified in the endonuclease
provided the original work is
properly cited. domains of POLE and POLD1 in CRC using a combination of QMC-PCR, COLD-PCR, HRM
analyses, and Sanger sequencing.
Publisher’s Note: AccScience
Publishing remains neutral with
regard to jurisdictional claims in
published maps and institutional Keywords: Colorectal cancer; Novel somatic mutations; POLE; POLD1
affiliations.

Volume 3 Issue 3 (2024) 1 doi: 10.36922/td.3659